Photographic light-screen.



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UNITED STATES Patented May 5, 1903.

PATENT OFFICE.

THOMAS WILLSIEp-F IONIA, MICHIGAN.

PHOTOJG RAPHIC LIGHT-SCREEN.

SPECIFICATION forming part of Letters Patent No. 727,524, dated May 5,1903.

Application led December 22, 1902. Serial No.v 136,200. (No model.)

To all who'm it may concern:

Be it known that I, THOMAS WILLsIE, a. citizen ofthe United States,residing at Ionia, in the county of Ionia and State of Michigan, haveinvented certain new and useful Improvements in PhotographicLight-Screens; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to improvements in photographic ray-iilters, andhas for its ultimate purpose the production of photographic printsrepresenting more especially landscape views having perfectly-balancedforeground and sky, as well as moving objects contained therein, such asmoving trains, landscape efg. fects during high winds, athletic sports,&c.

The object of my invention isto provide a ray-filter which is applicableto all kinds of photographic cameras, including those having both fixedfocus and focusing-lenses, to produce the above eects on a sensitiveplate or negative with a shorter exposure on any lens having my improvedray-filter used in combination therewith than could be produced withoutit and to produce one which is adapted for use in combination with allmakes of photographic plates or films in use at the present time, alsoone which is simple in its construction and which may he cheaply oreconomically manufactured and also which may be applied to any of theforms of lenstubes now in use; and, furthermore, it consists in theconstruction and arrangement of its parts, which will be more fullyhereinafter described, and definitely pointed out in the claims. Iattain these objects by means of the device herein described, andillustrated by the accompanying drawings, in which- Figure l illustratesan elevation, partly in section, showing my improved ray-filter asapplied to the lens of an ordinary photographic camera. Fig. 2illustrates an enlarged end view of myimproved device in detail,

shown as having been detached therefrom.-

Fig. 3 is a transverse vertical section of the same. Fig. 4 is atransverse vertical section of a modified form of myimproved ray-filterin detail, its casing or securing-frame having been removed therefrom.Fig. 5 is a diagrammatic view used to illustrate the principle on whichmy invention is based.

Referring to the drawings, Fig. l, A indicates the bellows of anordinary photographic camera.

B is the frame of the box, containing slides aand b, in which aresecured sensitive plates or films commonly used in the photographic art,and C the front portion thereof, to which is secured the bellows orfocusing portion A.

D is the lens-tube, having the internal frame E, in which the lens Fissecured. Said lens-tube D is secured within the front portion C by meansof the exterior ange G and screws H.

I indicates my improved ray-filter, which is secured to the outer end ofthe lens-tube D by means of the circular anged casing J. The inner edgeof said circular flanged casing J is made thinner in order to form ashoulder K, against which the ray-filter bears.

L is an internal ring placed within thecircular anged casing J to holdthe ray-filter I in position when it is desired at any time todisconnect said ray-filter I from the lens-tube D. It may be removedfrom the casing .l should it be desired to replace the ray-filter withanother in case of accident or for any other reason known to theoperator.

In the drawings, as above stated, I have shown my improved ray-filter asbeing attached to the outer end of a lens-tube; but it may also beattached to the inner end thereof as well with equally beneficialresults.

Referring to Figs. 1, 2, 3, and 4 of the drawings, it will be seen thatmy improved rayiilter in its entirety is composed of several strips oftransparent material dilerentially colored, each of one colorthroughoubpossessing light-transmitting qualities-such as glass properlyshaded, colors incorporated with gelatin on glass, or it may be composedofasingle strip of mica or Celluloid, as at M,

used as a base on which the various colors are arranged one aboveanother, their outer surfaces being parallel with each other and havingtheir edges slightly beveled to overlap each other in order to moreperfectly blend the said colors, and when in position at the end of thelens-tube D (shown in Fig. 1) they are arranged horizontally to it on aperpendicular plane therewith.

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To illustrate the fast working qualities of my improved ray-filter, itwill be necessary to explain, using the diagrammatic Fig. 5. It is awell-known principle that the heat or red rays are nearest the earth.Then follow, in their respective order, the orange, yellow, green, blue,indigo, and violet, the last named being the coldest rays, butpossessing the most actinic qualities. The aetinic value of said raysvaries mathematically as one to eight.

The im mediate foreground,represented by the red rays orcolor,(indicated as No. 1,) requires eight times the exposure of that of ,thesky, (represented by the violet rays or color No. 7.) By filtering withthe red or lowest, slowest colored rays, as indicated by No. 1, with theupper very fast violet rays (indicated by said No.' 7) the rays aremathematically balanced or qualified, thus making eight the act-inievalue of the combined result. tVith the orange rays (indicated by thecolor No. 2) are blended the indigo rays, as indicated by color No. G,thereby also making eight the aetinic value of the combined iesult,mathematically considered. The yellow rays (indicated by color No. 3)are blended with the blue rays, (indicated by No. 5,) which alsobalances the rays, making eight the aetinic value of the combinedresult, mathematically considered. The center color of the spectrum,green, having an actinic value of four, is filtered or mixed with thegreen color, (indicated by color No. 4,) which, as above described, alsomakes eight, the actinie Vallio of the combined result, mathematicallyconsidered. In other words, by the use of my improved ray-filter incombination with a lens-tube and camera the rays from the upper skyportion are blended with those of the immediate foreground, and theintermediate rays between the upper sky portion and the horizon areblended with the intermediate rays of the foreground, whereby aperfectly-balanced negative is produced, for the reason that the rays oflight passing through said ray-filter fall on all parts of the sensitiveplate alike. Thus it will be readily seen that this device retards orrestricts the upper portion of the spectrum, which is of a higheractinic value, down to its center and accelerates the lower half of thespectrum, which is of lower actinic value, upto its center, thus forminga balanced whole relatively slower than the highest actinic rays andrelatively faster than the lower actinic rays, the balance being theintermediate between the high actinic and low actinie values. Hence aspeed faster than normal is attained, as hereinafter stated.

I do not wish to limit myself to the exact widths and colors of stripsas indicated in the drawings, as I may use shades or tints of the samecolors as well; but the strips should be graduated in width from thecenter up and down, and the shades or tints used should balance eachother in the same manner as hereinbefore described.

I have by my improved ray-filter, used in combination with a camera andlens, produced negatives of landscapes which in the print showed verydistinct features both in landscape and cloud effects, the details inthe foreground being clearly defined even up to the horizon, as well asthe clouds in the sky. 'lhese were taken ou au exposure which wasseveral times faster than the normal` The sensitive plates were of thevarious kinds in common use.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. A ray-filter for photographic use consisting of transparent coloredstrips, s'o arranged as to gradually restrict, actinically, the actionof the-rays of light of a high actinic value passing through it down toits center, and to gradually accelerate, actinically, the action of thelow rays which are of a lower aetinic value passing through it up to itscenter, whereby all the rays of light passing through said ray-filterare perfectly balanced, and fall with equal actinic value on all partsof the sensitive plate.

2. A ray-filter for photographic use consisting of a series ofdifierentially-colored, transparent strips, each of one colorthroughout,

the top strip being of the most restricting color, of low actinic value,representing in use the upper sky portion, each consecutive strip ofcolor being of a gradually higher actinic value downward to its bottomwhere a tint Aof the highest actinic value is used representing the immediate foreground portion.

3. A ray-filter for photographic use consisting of a series ofdifferentially-colored strips, each of one color throughout, the topstrip being ot' the most restricting color of low actinic value, eachconsecutive strip of color being of a gradually higher actinic value,downward to its bottom, in combination with a casing for holding saidray-filter.

4. tray-filter for photographic use consisting of a series ofdilterentially-colored strips, each of one color throughout, the topstrip being of the most restricting color of low actinic value, eachconsecutive strip of color being of a gradually higher actinic valuedownward to its bottom, arranged one above another wit-h reference totheir actinic lighttransmitting qualities, graded from a low actinicvalue at its top to a high actinic value at its bottom, the whole beingadapted to'act at one time, in unison, upon a sensitive plato.

5. A ray-filter for photographic use consisting of a series oftransparent strips, differentially colored, each ot one colorthroughout, arranged one above another, the top strip being of the mostrestricting color of low actinic value, each consecutive strip of colorbeing of a higher actinic value downward toits bottom, in combinationwith a casing and means for holding said ray-filter within said casing.

G. A ray-filter for photographic use consisting of a series oftransparent, differentially- ICO IIO

colored strips, each of one color throughout, arranged one aboveanother, the top strip being of a' low actinic value, each consecutivestrip of color being of a higher actinic value` downward to its bottom,the whole outer surfaces being parallel to each other, and adjoiningedges beveled thereto, in combination with a casinghaving a shoulderformed therein, and means for holding said rayfilter against saidshoulder.

7. A ray-filter for photographic use oomposed of aseriesoftransparent,dierentiallycolored strips, each of one color throughout,the top strip being of the most light-restricting color of low actinicvalue, each consecutive istrip of color being of gradually higheractinic value downward to its bottom, the whole being arranged one aboveanother, horizontally to its perpendicular width, in combination with acasing, and means for holding said ray-filter within said casing.

8. A ray-filter for photographic use coinposed of a single piece oftransparent material forming a base on which a series of transparent,differentially-colored strips, each of one color throughout, arearranged one above another, the top strip representing the upper skyportion being of the lowest actinic value, each consecutive strip ofcolor being of a gradually higher actinic value downward to its bottomwhere the strip of color is of the highest or accelerating actinicvalue, representing the immediate foreground portion, the whole beingarranged horizontally to its perpendicular width.

9. A ray-lter for photographic use composed of a single piece oftransparent matelrial forming a base on which a series of transparent,differentially-colored strips, each of one color throughout, arearranged one above another, the top strip of color being of thc lowestactinic value, each consecutive strip of color being of a graduallyhigher actinic Y"value downward to its bottom, the whole beparent,differentially-colored strips, each of one color, are arranged one aboveanother, graded from a strip of low actinic value at its top, eachconsecutive strip of color being of a higher actinic Value downward toits bottom, the whole being arranged horizontally to its perpendicularwidth, in combination with a casing having a shoulder formed therein,and means for holding said ray-filter against said shoulder.

1l. A ray-lter for photographic use consisting of a single piece oftransparent material forming a base on which a series of transparent,dierentially-colored strips, each of one color, are arranged one aboveanother, with reference to their different actinic lightfilteringqualities, graded from a strip of color of low actinic quality at itstop, each coliseoutive strip of color being of a higher actinic valuedownward to its bottom, their outer surfaces being parallel t0 eachother, and adjoining edges overlapping thereto, in combination with acasing, and means for holding said ray-filter within said casing.

In testimony whereof I ailix my signature in presence of two witnesses.THOMAS YVILLSIE. Witnesses:

R. H. SToCoUM, MADORA B. WILLSIE.

